I just read a number of the entries on the link Blue Ridge provided, and in one of those entries it stated that K&N filters are fine for the street, but they do allow foreign particles of a greater size than a paper filter. My experience supports that claim. When I lived out West (where the climate is drier and the air more likely to carry such particles than in the humid East), K&Ns were OK on the street, but offroad, the volume of dust created seemed to overwhelm the K&N, and another air filtration system was required. But here in the humid Southeast, they are the economical way to go.

That is an interesting read. I suppose it's a risk you take with any low restriction air filter (S&B for example). I've never had anything but the stock filter on my bike, but have been considering going with a flatslide carb and K&N combo next summer. Of course, no one has ever accused Western Washington of being dry and dusty, so I doubt it would be an issue for me (at least on this side of the Cascades).

Gauze (K&N) and foam (UNI) filters must be oiled to work. These mediums have larger holes than paper for better air flow, The holes don't go straight through. It is kind of like a honey comb with lots of turns in the passageways. The dirt has momentum that keeps it heading to the wall of the passage as the air wends through. The dirt then sticks to the oiled walls of the passage. If the filter is dry the dirt just blows on through. If the oil dries out or can't hold any more dirt, the dirt then is sucked through. If properly serviced these filters work better and longer and with less restriction than paper. Also, when properly oiled the weak point is the mating surface where the filter meets the box or mount. This needs to be sealed with grease on installation. They must be serviced regularly. On my dirt bike this means EVERY ride. On a street bike adjust service frequency to accommodate time and riding conditions. Use the right oil/ K&N uses a specific oil formulated for gauze. Any other oil will clog the filter. Foam filters will work with any oil, but regular oil gets sucked through quickly. Foam filter specific oil lasts much longer.

My first bikes (60's) had velocity stacks, not for filtering, but they were neat !!!I would have to clean the carb's a lot. and I'm sure they were scouring the cylinder walls, galling the guides, but,,, they were neat !!! I still got over 100 K on most of these bikes

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99 Enfield Bullet 535a man isn't drunk,if he can lie on the floor without hanging on

I've read stuff like that advrider thread many times.And there probably is something to it. The K&N is a free-flowing filter, and probably actually does allow a slight amount more particulates thru into the engine. Probably not alot more, but maybe some more.

You find posts like that on forums where there is a big accent on longevity of the engines, such as on BMW forums. And also on other "hi-miler" type forums where they are big on engine longevity.

The truth is that no Bullet is ever going to hit 100k miles without a rebuild, no matter what filter you use, so it's all a moot point.Back in "the day", a Brit bike was lucky to get 20k miles between rebuilds. And I'd say that also holds for most modern Bullets. Yes, I've read some accounts of 40k miles or even 50k miles, but I guarantee you those bikes are about "plum wore out".

I really strongly doubt that the selection of your air filter is going to make a major difference in the longevity of your Bullet between rebuilds.If I got 20k miles out of my Bullet between rebuilds, I'd be happy as a pig in shit.

I've read stuff like that advrider thread many times.And there probably is something to it. The K&N is a free-flowing filter, and probably actually does allow a slight amount more particulates thru into the engine. Probably not alot more, but maybe some more.

You find posts like that on forums where there is a big accent on longevity of the engines, such as on BMW forums. And also on other "hi-miler" type forums where they are big on engine longevity.

The truth is that no Bullet is ever going to hit 100k miles without a rebuild, no matter what filter you use, so it's all a moot point.

Back in "the day", a Brit bike was lucky to get 20k miles between rebuilds. And I'd say that also holds for most modern Bullets. Yes, I've read some accounts of 40k miles or even 50k miles, but I guarantee you those bikes are about "plum wore out".

I really strongly doubt that the selection of your air filter is going to make a major difference in the longevity of your Bullet between rebuilds.If I got 20k miles out of my Bullet between rebuilds, I'd be happy as a pig in shit.

To what do you attribute such a short life before rebuild? Indian mettalurgy? Design? I ask because the Ural is a pretty primitive design and you don't exactly use the words "Russian" and "Craftsmanship" in the same sentence, but there are a lot of Urals going 100K plus.

To what do you attribute such a short life before rebuild? Indian mettalurgy? Design? I ask because the Ural is a pretty primitive design and you don't exactly use the words "Russian" and "Craftsmanship" in the same sentence, but there are a lot of Urals going 100K plus.

If I were to pin it on one particular thing, I'd say it was due to the very minimal oiling system that is in the Bullet design. And perhaps a bit of the vibration issue, since it's a single that vibrates due to inherent unbalance.The crank is the only thing that's pressure-fed, and that is at a very low rate.The piston/cylinder is splash-oiled, main bearings are drip-oiled by whatever splash makes it over into their vicinity, and the scavenge pump only minimally oils the top end.Oil flow is only about six- tenths of a cc of oil with every 12 revolutions of the crankshaft.Hi-volume pumps almost double that amount,but it is still an insufficient oiling system for heavy duty or extended duty use.It is meant to be rebuilt fairly regularly, and it is a simlple engine to rebuild.I believe it was designed to be refreshed internally at shorter intervals than other engines, as part of the normal maintenance schedule for long term use.

Other engine designs accent longevity without refreshing, and are more complex and expensive in their approach, so they design for longevity. The Bullet is barely above a lawn mower engine in complexity, and I think it was viewed to be as easy to maintain as a lawn mower, and viewed as a simple procedure.

With a simple teardown, and replacement of rings, main bearings, floating bush, and rockers, it can be back on the road in a week-end. At a relatively low cost.Perhaps add an oil-pump drive spindle, if necessary. When the bore wears too big, a simple bore job and a new oversize piston and ring set puts you back on the road.

At the time this bike was designed, these procedures were well within the expected abilities of the owner, or a fairly inexpensive job at the repair shop.If I had the proper parts on hand, I could rebuild a Bullet engine and have it back in the bike and running, in less time than it takes to replace a water pump on a Jaguar.

The Urals are a different animal altogether. I don't know what their oiling system is, but I know they are a horizontally-opposed twin with inherent balance of the engine, and cylinders which lay down in a wet sump for easier oiling, and are at least somewhat of a derivation of the BMW twin, which approached longer engine life at a higher priority. Since there are two of almost everything on a twin, complexity and expense are increased, and thus the cost of the rebuild.

At the time the Bullet was designed, 100k miles was a very long life for an engine, and most never would make 100k. A valve job was necessary at about 50k-60k miles.And this was in water-cooled cars of the time.Very few MG or Triumph cars would go 100k without a rebuild, and none of them would go over 70k without a valve job. Rebuilds were a normally expected part of owning a car or bike, over the long term.That's just the way things were back then.Most things of that time were made to be rebuilt. Most things today are made to be thrown away after a certain life, because they are obsolete. People just buy new ones.Different way of looking at things, from a design perspective.

The UCEs will easily go well over 20,000 miles. Ace's observations were quite true with vintage English bikes, regardless of make, including iron barrels, but the new metallurgy and oiling system in the UCEs has helped the life expectancy of the UCEs considerably! Jack had about 23,000 on his G5 when it was stolen and it was running great. No oil consumption, no problems. It probably wouldn't have made 100,000 miles, but then the shear limitations of an aircooled thumper are still at work. As far as K&Ns go, they really don't let anything bigger through than the paper filters because the oil itself reduces the size of the holes in the filter material. And the shape of the tunnels will catch stuff that a paper filter won't. I like them a lot. Recommended.Not a UNI fan. When I worked in the Triumph/BSA/Norton shop we tried UNIs and found that occasionally they would richen up the mixture so badly that the bikes wouldn't even run at full throttle. They definitely didn't flow with the K&Ns or stock paper filters.Bare

Although the RE engines are air cooled, which doesn't contribute to long life, I fully expect a UCE engine to easily go over 30,000 miles (48,000km) without a wear issue.

As for the K&N filter that was designed for the Royal Enfield UCE powered motorcycles, I had rather poor luck with the one I bought.It decreased the engine power and greatly reduced the fuel economy. My milage dropped from around 74 mpg (US gallons) to around 50 mpg.

The $50 filter is now resting on a shelf in my storage room while I happily motor down the road using the OEM paper filter in my G5.

I "cleaned" my air filter as recommended by the manual - battered it against the bench a few times and blew some compressed air from the outside to clear the inner pleats... the air is drawn from the inside, don'cha know?

I was gobsmacked by the quantity of debris that I was able to shake from the filter! And not just dust - dirt and sand! I guess it makes sense - the opening to the filter, on the inside of the right-hand "tool-box", is right next to the rear wheel, which kicks plenty of dirt around...